package leetcode.code1408;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import leetcode.IDebug;

//执行用时：8 ms, 在所有 Java 提交中击败了9.47%的用户
//
//内存消耗：42.1 MB, 在所有 Java 提交中击败了5.10%的用户
//
//通过测试用例：67 / 67
public class Solution2 implements IDebug {

	public List<String> stringMatching(String[] words) {
		Set<String> ans = new HashSet<>();
		for (int i = 0; i < words.length; i++) {
			String word1 = words[i];
			for (int j = i + 1; j < words.length; j++) {
				String word2 = words[j];
				if (word1.length() < word2.length()) {
					if (this.kmp(word2, word1)) {
						ans.add(word1);
					}
				} else {
					if (this.kmp(word1, word2))
						ans.add(word2);
				}
			}
		}
		return new ArrayList<>(ans);
	}

	public boolean kmp(String haystack, String needle) {
		char[] chars1 = haystack.toCharArray();
		char[] chars2 = needle.toCharArray();
		int len1 = chars1.length;
		int len2 = chars2.length;
		int[] p = new int[len2];
		// p中m位置记录数值n,表示[0,n-1]的字符串同[m-n+1,m]字符串相同
		for (int i = 1, j = 0; i < len2 && j < len2; i++) {
			while (j > 0 && chars2[j] != chars2[i]) {
				j = p[j - 1];
			}
			if (chars2[i] == chars2[j]) {
				j++;
			}
			p[i] = j;
		}
		for (int i = 0, j = 0; i < len1 && j < len2; i++) {
			while (j > 0 && chars2[j] != chars1[i]) {
				j = p[j - 1];
			}
			if (chars2[j] == chars1[i]) {
				j++;
			}
			if (j == len2) {
				return true;
			}
		}
		return false;
	}

	@Override
	public void debug4() {
		// TODO Auto-generated method stub

	}

	@Override
	public void debug3() {
		// TODO Auto-generated method stub

	}

	@Override
	public void debug2() {
		// TODO Auto-generated method stub

	}

	@Override
	public void debug1() {
		// TODO Auto-generated method stub

	}

	public static void main(String[] args) {
		Solution2 so = new Solution2();
		so.debug1();
		so.debug2();
		so.debug3();
		so.debug4();

	}

}
